noise in fuel tank on my 95 bmw 740i E38

there was a humming noise come from the back seat area... so
suspected the fuel pump and put in a nea one... But the noise did not
go away. I then changed the fuel sending unit on the left side
because the noise seemed to be coming from there. But the noise did
not go away... Before doing anything else I want to know what else
should I check... or what else could it be that is causing that noise

> wrote in message
...
> there was a humming noise come from the back seat area... so
> suspected the fuel pump and put in a nea one... But the noise did not
> go away. I then changed the fuel sending unit on the left side
> because the noise seemed to be coming from there. But the noise did
> not go away... Before doing anything else I want to know what else
> should I check... or what else could it be that is causing that noise


Diff - is the noise worse in reverse or sharp corners?
This can often be ignored - I had one whirr in reverse for 11 years
until I sold the car.

It's the fuel pump.

Just because you can hear the pump does not mean anything.



> wrote in message
...
> there was a humming noise come from the back seat area... so
> suspected the fuel pump and put in a nea one... But the noise did not
> go away. I then changed the fuel sending unit on the left side
> because the noise seemed to be coming from there. But the noise did
> not go away... Before doing anything else I want to know what else
> should I check... or what else could it be that is causing that noise

On Jul 27, 2:39 am, BBO > wrote:
> wrote:
> > not go away... Before doing anything else I want to know what else
> > should I check... or what else could it be that is causing that noise
>
> Rear wheel bearing?
>
> --
> You can't be a rational person six days a week...and on one day of the
> week, go to a building, and think you're drinking the blood of a two
> thousand year old space god. -- Bill Maher

it makes the noise while standing still and the transmission in park.
I dont think it the bearing.

On Jul 27, 5:46 am, "R. Mark Clayton" >
wrote:
> > wrote in message
>
> ...
>
> > there was a humming noise come from the back seat area... so
> > suspected the fuel pump and put in a nea one... But the noise did not
> > go away. I then changed the fuel sending unit on the left side
> > because the noise seemed to be coming from there. But the noise did
> > not go away... Before doing anything else I want to know what else
> > should I check... or what else could it be that is causing that noise
>
> Diff - is the noise worse in reverse or sharp corners?
> This can often be ignored - I had one whirr in reverse for 11 years
> until I sold the car.

the noise it just there all the time. 10 seconds after starting the
car the noise starts up.... It is coming from the gas tank area. And
is muffled a little when the sound deadening pad is replace onto the
fuel pump access cover plate. but its there even in park

On Jul 27, 1:50 pm, "Jeff Strickland" > wrote:
> It's the fuel pump.
>
> Just because you can hear the pump does not mean anything.
>
> > wrote in message
>
> ...
>
> > there was a humming noise come from the back seat area... so
> > suspected the fuel pump and put in a nea one... But the noise did not
> > go away. I then changed the fuel sending unit on the left side
> > because the noise seemed to be coming from there. But the noise did
> > not go away... Before doing anything else I want to know what else
> > should I check... or what else could it be that is causing that noise

I replaced the old fuel pump with a new one already and the new is
still there. The pump that is in there now is only 3 days old

> wrote in message
...
> On Jul 27, 1:50 pm, "Jeff Strickland" > wrote:
>> It's the fuel pump.
>>
>> Just because you can hear the pump does not mean anything.
>>
>> > wrote in message
>>
>> ...
>>
>> > there was a humming noise come from the back seat area... so
>> > suspected the fuel pump and put in a nea one... But the noise did not
>> > go away. I then changed the fuel sending unit on the left side
>> > because the noise seemed to be coming from there. But the noise did
>> > not go away... Before doing anything else I want to know what else
>> > should I check... or what else could it be that is causing that noise
>
> I replaced the old fuel pump with a new one already and the new is
> still there. The pump that is in there now is only 3 days old



If the noise starts when you turn the key on, it's the pump. If the noise
does not start until you are driving, then it could be the diff.

> wrote:
>
>it makes the noise while standing still and the transmission in park.
>I dont think it the bearing.

Does it make the sound with the gas cap off? You can sometimes get
funny noises from the tank venting system.

If it is the fuel pump, it will usually be much louder when the tank
is low than when the tank is full.

Some fuel pumps are just noisy. Life is like that.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

> wrote in message
...
> On Jul 27, 5:46 am, "R. Mark Clayton" >
> wrote:
>> > wrote in message
>>
>> ...
>>
>> > there was a humming noise come from the back seat area... so
>> > suspected the fuel pump and put in a nea one... But the noise did not
>> > go away. I then changed the fuel sending unit on the left side
>> > because the noise seemed to be coming from there. But the noise did
>> > not go away... Before doing anything else I want to know what else
>> > should I check... or what else could it be that is causing that noise
>>
>> Diff - is the noise worse in reverse or sharp corners?
>> This can often be ignored - I had one whirr in reverse for 11 years
>> until I sold the car.
>
> the noise it just there all the time. 10 seconds after starting the
> car the noise starts up.... It is coming from the gas tank area. And
> is muffled a little when the sound deadening pad is replace onto the
> fuel pump access cover plate. but its there even in park

Fuel pump then - look for a leak and bleed the line.

Is there any sort of a pressure switch which should switch it off once
satisfactory pressure is achieved?


PS my third 735i used to whirr for a few seconds after switch on while it
pressurised the fuel line - it was best to wait for this to end before
trying to start the engine.

> wrote in message
...
> there was a humming noise come from the back seat area... so
> suspected the fuel pump and put in a nea one... But the noise did not
> go away. I then changed the fuel sending unit on the left side
> because the noise seemed to be coming from there. But the noise did
> not go away... Before doing anything else I want to know what else
> should I check... or what else could it be that is causing that noise
CD player back there gone bad?